The present invention relates to an apparatus for cleaning a tank-like vessel and more particularly to an apparatus for cleaning the inside of a tank-like vessel such as a reactor, a storage tank, a dissolver, and a scrubber.
Hitherto, there have been known, as apparatuses for cleaning tank-like vessels, a jet gun system using a jet gun which blows a high-pressure water in one direction, and a lance system using a multi-dimensional nozzle capable of blowing a high-pressure water in a two-dimensional direction or a three-dimensional direction.
The above-mentioned jet gun system is such a system wherein a worker with a jet gun directs the gun against a portion to be cleaned. The jet gun system is often used in the case of low-pressure cleaning or under good working conditions thanks to its simplicity.
The above-mentioned lance system includes a fixed lance system using a lance of which length is fixed, and an expansion lance system using an expansible lance. These two systems, i.e. a fixed lance system and an expansion lance system, are suitable for automatic cleaning because of the use of multi-dimensional nozzles.
However, the above-mentioned jet gun system has the following drawbacks.
(1) Because of the manual operation, the reaction of jet water is enlarged when heightening the pressure of supply water. Therefore, a strong power is required to support a jet gun.
(2) If a portion to be cleaned is distant from a worker, a gun is required to be connected to a lance in order to approach the portion to be cleaned. In that case, the operation of the gun becomes considerably hard because of the difficulty in supporting a weight of the gun and lance. It is therefore, impossible to work for a long period of time with the gun.
(3) When cleaning the inside of a vessel from the outside, cleanable area is limited to the vicinity of an upper opening of a vessel.
(4) There is inevitably made dead space because the lance system uses a straight water jet. Accordingly, many portions are likely to be left uncleaned.
(5) When a worker operates a jet gun in a vessel, a perfect cleaning is actually very difficult, because a scaffold is difficult to certainly set up and it is difficult to make sure portions to be cleaned due to the poor visibility by floating water droplets.
On the other hand, the above-mentioned lance system has the following drawbacks.
(1) A lance is required to have a strong construction because the lance is subjected to the reaction of jet water. The weight of the lance becomes large, and accordingly the size of the whole equipment supporting the lance becomes large and the weight thereof also becomes large.
(2) Because of a large size and weight of the equipment, there are required a large-scale conveyor such as a truck and a large working space, which raises a cost of the equipment.
(3) The most serious disadvantage of the lance system is that, both in the case of a fixed lance system and an expansion lance system, the insertion direction of a cleaning nozzle is limited to a direction straight from a portion whereinto the lance is inserted because the lance has such a construction that it is straightly extended in one direction. There is generated, therefore, dead space when a portion to be cleaned is far away from a portion whereinto the lance is inserted or the vessel has a touch of complicated construction, whereby the perfect cleaning cannot be expected.
(4) The cleanable area is limited to the upper portion of the vessel, i.e. the vicinity of the opening in the case of a fixed lance system. Further, even in the case of an expansion lance system, the perfect cleaning cannot be expected with respect to a large-scale vessel due to the limitation in the length of a lance.
Besides above-mentioned drawbacks, both in the case of a fixed lance system and an expansion lance system, the cleaning power is remarkably weakened due to the reduction of impact power of jet water when a portion to be cleaned is far away from a cleaning nozzle.
An object of the present invention is to provide an apparatus which is easy to handle and enables the perfect cleaning of the inner surface of a tank-like vessel.